Porphobilinogen deaminase (PBGD), the third enzyme in the heme biosynthesis, catalyzes the sequential coupling of four porphobilinogen (PBG) molecules into a heme precursor. Mutations in PBGD are associated with acute intermittent porphyria (AIP), a rare metabolic disorder. We used Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to demonstrate that wild-type PBGD and AIP-associated mutant R167W both existed as holoenzymes (Eholo) covalently attached to the dipyrromethane cofactor, and three intermediate complexes, ES, ES2, and ES3, where S represents PBG. In contrast, only ES2 was detected in AIP-associated mutant R173W, indicating that the formation of ES3 is inhibited. The R173W crystal structure in the ES2-state revealed major rearrangements of the loops around the active site, compared to wild-type PBGD in the Eholo-state. These results contribute to elucidating the structural pathogenesis of two common AIP-associated mutations and reveal the important structural role of Arg173 in the polypyrrole elongation mechanism.Black tea is the most widely consumed tea drink in the world and has consistently been reported to possess anti-aging benefits. However, whether theaflavins, one type of the characteristic phytochemicals in black tea extracts, are involved in regulating aging and lifespan in consumers remains largely unknown. In this study, we show that theaflavins play a beneficial role in preventing age-onset intestinal leakage and dysbiosis, thus delaying aging in Drosophila. Mechanistically, theaflavins regulate the condensate assembly of Imd to negatively govern the overactivation of Imd signals in fruit fly intestines. In addition, theaflavins prevent DSS-induced colitis in mice, suggesting theaflavins play a role in modulating intestinal integrity. Overall, our study reveals a molecular mechanism by which theaflavins regulate gut homeostasis likely through controlling Imd coalescence.Obesity is an important risk factor and a potential treatment target for hepatic steatosis. The maladaptation of hepatic mitochondrial flexibility plays a key role in the hepatic steatosis. Herein, we found that hepatocyte-like cells derived from human adipose stem cell of obese patients exhibited the characteristics of hepatic steatosis and accompanied with lower expression of the subunits of mitochondrial complex I and lower oxidative phosphorylation levels. The GSK3 inhibitor CHIR-99021 promoted the expression of NDUFB8, NDUFB9, the subunits of mitochondrial complex I, the basal oxygen consumption rate, and the fatty acid oxidation of the hepatocytes of obese patients by upregulating the expression of the transcription factor PGC-1α, TFAM, and NRF1 involved in mitochondrial biogenesis. Moreover, CHIR-99021 decreased the lipid droplets size and the triglyceride levels in hepatocytes of obese patients. The results demonstrate that GSK3 inhibition ameliorates hepatic steatosis by elevating the mitochondrial function in hepatocytes of obese patients.RNA viruses are responsible for many zoonotic diseases that post great challenges for public health. Effective therapeutics against these viral infections remain limited. Here, we deployed a computational framework for host-based drug repositioning to predict potential antiviral drugs from 2,352 approved drugs and 1,062 natural compounds embedded in herbs of traditional Chinese medicine. By systematically interrogating public genetic screening data, we comprehensively cataloged host dependency genes (HDGs) that are indispensable for successful viral infection corresponding to 10 families and 29 species of RNA viruses. We then utilized these HDGs as potential drug targets and interrogated extensive drug-target interactions through database retrieval, literature mining, and de novo prediction using artificial intelligence-based algorithms. Repurposed drugs or natural compounds were proposed against many viral pathogens such as coronaviruses including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), flaviviruses, and influenza viruses. This study helps to prioritize promising drug candidates for in-depth evaluation against these virus-related diseases.Single-cell transcriptomics suffer from sensitivity limits that restrict low abundance transcript identification, affects clustering and can hamper downstream analyses. Here, we describe Constellation sequencing (Constellation-Seq), a molecular transcriptome filter that delivers two orders of magnitude sensitivity gains by maximizing read utility while reducing the data sparsity and sequencing costs. The technique reliably measures changes in gene expression and was demonstrated by resolving rare dendritic cell populations from a peripheral blood mononuclear cell sample sample and exploring their biology with extreme resolution. The simple and powerful method is fully compatible with standard scRNA-Seq library preparation protocols and can be used for hypothesis testing, marker validation or investigating pathways.Stress-coupled NEDDylation potentially regulates the aggregation of nuclear proteins, which could protect the nuclear ubiquitin-proteasome system from proteotoxic stress. However, it remains unclear how NEDDylation controls protein-aggregation responses to diverse stress conditions. Here, we identified HDAC6 as a direct NEDD8-binding partner that regulates the formation of aggresome-like bodies (ALBs) containing NEDDylated cytosolic protein aggregates during ubiquitin stress. https://www.selleckchem.com/products/zcl278.html HDAC6 colocalizes with stress-induced ALBs, and HDAC6 inhibition suppresses ALBs formation, but not stress-induced NEDDylation, suggesting that HDAC6 carries NEDDylated-proteins to generate ALBs. Then, we monitored the ALBs-associated proteostasis network and found that p62 directly controls ALBs formation as an acceptor of NEDDylated cytosolic aggregates. Interestingly, we also observed that ALBs are highly condensed in chloroquine-treated cells with impaired autophagic flux, indicating that ALBs rely on autophagy. Collectively, our data suggest that NEDD8, HDAC6, and p62 are involved in the management of proteotoxic stress by forming cytosolic ALBs coupled to the aggresome-autophagy flux.